1. Field of the Invention
The present invention relates generally to the field of protective coverings for windscreens and, more specifically, to a transparent laminated structure having multiple peel-away film layers for protecting windscreens of rotary aircraft.
2. Description of the Related Art
The degradation of aircraft windscreens is a costly problem that also effects safety and mission effectiveness due to distortion of visual and RF electromagnetic wavelengths that pass through a damaged windscreen or sensor window. As such, clarity through aircraft windscreens and sensor windows is imperative for proper operation of an aircraft.
Currently, rotary aircraft windscreens and sensor windows are unprotected from environmental damage. As such, the windscreens and sensor windows quickly degrade with scratches and cracks, distorting visible and RF electromagnetic wavelengths that pass there-through. Accordingly, a pilot's or crew member's visibility, his use of night vision goggles, and/or the operation of sensors are impaired which may cause operator error and/or sensor errors, thereby inhibiting mission effectiveness. Additionally, small fissures and defects in the windscreen may be propagated by stress and vibrations during aircraft use, rendering the windscreen entirely unsatisfactory.
The rate of windscreen deterioration is particularly problematic with helicopters, especially those that are performing desert missions since, in addition to blowing sand and debris, the rotor blades of the helicopter and neighboring helicopters can disturb sand and rocks causing a whirlwind of abrasive particles.
Traditionally, various polishes have been used to remove scratches from marred aircraft windscreens. However, the polishing process is not only time consuming, but also may leave swirl marks that dramatically distort the passage of visible and RF electromagnetic wavelengths through the windscreen.
By having no current means to protect windscreens and only a limited ability to recondition the same, aircraft windscreens quickly degrade beyond acceptable standards and require replacement; an expensive and time consuming process.
In the art of vehicle racing such as NASCAR®, multi-layered transparent film has been used to extend the useful life of a vehicle's windshield. However, such automotive films are not suitable for usage in the art of rotary aircraft due to a multitude of limitations.
First, electrostatic surface dissipation is extremely slow through automotive films as compared to an aircraft window. As such, if automotive film was used on an aircraft, precipitation static charging of the film could cause unwanted electrical interference in aircraft electrical equipment; disrupting the equipment and presenting a safety hazard. Electrostatic charging is particularly problematic in a dry dusty environment such as the desert.
Additionally, automotive films may not suitably perform under the operational conditions at which a rotary aircraft is subjected. For example, if an automotive film was used on an aircraft, the adhesion between the vehicle film and an aircraft windscreen could fail due to high windshear forces and/or high temperatures that may be experienced during aircraft usage.
Moreover, automotive films are not sufficiently constructed to absorb the type of impact that may be experienced by an aircraft windscreen, such as rocks that are kicked-up by the rotor blades.
Since degradation of an aircraft windscreen reduces pilot and sensory effectiveness, there is, therefore, a need in the art to provide a transparent laminated structure having multiple film layers for protecting windscreens from damage. Additionally, there exists a need in the art for a transparent laminated structure that is suitable for being used under the environmental conditions experienced by rotary aircraft. There further exists a need in the art of a transparent laminated structure that has an electrostatic dissipation rate that is sufficient to obviate potential arc-over from the structure.